避免字符串替换中的 for 循环？

我有数据、一个字符向量（最终我会折叠它，所以我不在乎它是否仍然是一个向量或是否被视为单个字符串）、一个模式向量和一个替换向量。我希望数据中的每个模式都被其各自的替换所替换。我用一个完成了stringr和一个 for 循环，但是有没有更类似于 R 的方法来做到这一点？

require(stringr)
start_string <- sample(letters[1:10], 10)
my_pattern <- c("a", "b", "c", "z")
my_replacement <- c("[this was an a]", "[this was a b]", "[this was a c]", "[no z!]")
str_replace(start_string, pattern = my_pattern, replacement = my_replacement)
# bad lengths, doesn't work

str_replace(paste0(start_string, collapse = ""),
    pattern = my_pattern, replacement = my_replacement)
# vector output, not what I want in this case

my_result <- start_string
for (i in 1:length(my_pattern)) {
    my_result <- str_replace(my_result,
        pattern = my_pattern[i], replacement = my_replacement[i])
}
> my_result
 [1] "[this was a c]"  "[this was an a]" "e"               "g"               "h"               "[this was a b]" 
 [7] "d"               "j"               "f"               "i"   

# This is what I want, but is there a better way?

就我而言，我知道每种模式最多会出现一次，但并非每种模式都会出现。我知道我可以使用str_replace_all模式是否可能出现多次；我希望解决方案也能提供这种选择。我还想要一个使用的解决方案my_pattern and my_replacement这样它就可以成为以这些向量作为参数的函数的一部分。

我敢打赌还有另一种方法可以做到这一点，但我的第一个想法是gsubfn:

my_repl <- function(x){
    switch(x,a = "[this was an a]",
             b = "[this was a b]",
             c = "[this was a c]",
             z = "[this was a z]")
}

library(gsubfn)    
start_string <- sample(letters[1:10], 10)
gsubfn("a|b|c|z",my_repl,x = start_string)

如果您正在搜索列表元素的可接受的有效名称的模式，这也将起作用：

names(my_replacement) <- my_pattern
gsubfn("a|b|c|z",as.list(my_replacement),start_string)

Edit

但坦率地说，如果我真的必须在自己的代码中经常这样做，我可能会这样做for循环事物，包装在函数中。这是一个简单的版本，使用sub and gsub而不是来自的函数stringr:

vsub <- function(pattern,replacement,x,all = TRUE,...){
  FUN <- if (all) gsub else sub
  for (i in seq_len(min(length(pattern),length(replacement)))){
    x <- FUN(pattern = pattern[i],replacement = replacement[i],x,...)
  }
  x
}

vsub(my_pattern,my_replacement,start_string)

但当然，没有众所周知的内置函数的原因之一可能是像这样的顺序替换不会非常脆弱，因为它们是如此依赖于顺序：

vsub(rev(my_pattern),rev(my_replacement),start_string)
 [1] "i"                                          "[this w[this was an a]s [this was an a] c]"
 [3] "[this was an a]"                            "g"                                         
 [5] "j"                                          "d"                                         
 [7] "f"                                          "[this w[this was an a]s [this was an a] b]"
 [9] "h"                                          "e"